Tray application and Dolphin integration for Syncthing
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Martchus be92d5366c Show name instead of ID in recent changes 1 week ago
.github/ISSUE_TEMPLATE Add CLI to components in issue template 1 year ago
cli Use resource lock to avoid concurrent execution of tests requiring Syncthing test instance 2 weeks ago
connector Use resource lock to avoid concurrent execution of tests requiring Syncthing test instance 2 weeks ago
fileitemactionplugin Simplify coloring of common ForkAwesome icons 2 weeks ago
include Better decouple syncthingwidgets from libsyncthing if libsyncthing is disabled 9 months ago
libsyncthing Fix typo in libsyncthing tests 2 weeks ago
model Show name instead of ID in recent changes 1 week ago
plasmoid Use ForkAwesome icons also in RecentChangesPage of Plasmoid 2 weeks ago
scripts Use Boost.Process for launcher to cope with further sub processes 4 months ago
testhelper Use resource lock to avoid concurrent execution of tests requiring Syncthing test instance 2 weeks ago
tray Remove icons which are no longer needed 2 weeks ago
widgets Remove icons which are no longer needed 2 weeks ago
.gitignore Use Go modules for building libsyncthing 2 years ago
.gitmodules Add experimental 'libsyncthing' 4 years ago
CMakeLists.txt Use ForkAwesome consistently in Plasmoid as well 2 weeks ago
LICENSE Initial import 5 years ago Add licensing info for Windows distribution 2 years ago Fix references to README section "Known bugs and workarounds" 3 weeks ago

Syncthing Tray

  • Qt-based tray application
  • Dolphin/Plasma integration
  • command-line interface
  • Qt-ish C++ interface to control Syncthing

Checkout the official forum thread for discussions and announcement of new features.

Issues can be created on GitHub but please read the "Known bugs and workarounds" section in this document before.

I provide binaries/repositories for some platforms. There are also binaries/repositories provided by other distributors. For a list with links, checkout the Download section of this document. The release section on GitHub only contains a fraction of the available options.

Supported platforms

  • Designed to work under any desktop environment supported by Qt with tray icon support (can be shown as regular window if tray icon support is not available)
  • No desktop environment specific libraries required (only for optional features/integrations)
  • Tested under
    • X Window System
      • Plasma 5 (beside Qt Widgets based version there is a native "Plasmoid")
      • Openbox/lxqt/LXDE
      • Openbox/qt5ct/Tint2
      • Awesome/qt5ct
      • Cinnamon (native look and feel using adwaita-qt)
      • Deepin Desktop Environment
      • Xfce
    • Wayland
      • Plasma 5
      • Sway/Swaybar/Waybar
    • Windows 10
    • macOS 10.14 Mojave

If you can confirm it works under other desktop environments, please add it to the list. The section "Known bugs and workarounds" below contains information and workarounds for certain caveats.


  • Provides quick access to most frequently used features but does not intend to replace the official web UI
    • Check state of directories and devices
    • Check current traffic statistics
    • Display further details about directories and devices, like last file, last scan, items out of sync, ...
    • Display ongoing downloads
    • Display Syncthing log
    • Trigger re-scan of a specific directory or all directories at once
    • Open a directory with the default file browser
    • Pause/resume a specific device or all devices at once
    • Pause/resume a specific directory
    • View recent history of changes (done locally and remotely)
  • Shows notifications
    • The notification to show is configurable
    • Uses Qt's notification support or a D-Bus notification daemon directly
  • Reads connection parameters from Syncthing config file for quick setup (when just connecting to local instance)
  • Allows monitoring the status of the Syncthing systemd unit and to start and stop it (see section Configuring systemd integration)
  • Provides an option to conveniently add the tray to the applications launched when the desktop environment starts
  • Can launch Syncthing automatically when started and display stdout/stderr (useful under Windows)
  • Provides quick access to the official web UI
    • Utilizes either Qt WebEngine or Qt WebKit
    • Can be built without web view support as well (then the web UI is opened in the regular browser)
  • Allows switching quickly between multiple Syncthing instances
  • Also features a simple command line utility syncthingctl
    • Check status
    • Trigger rescan/pause/resume/restart
    • Wait for idle
    • View and modify raw configuration
    • Supports Bash completion, even for directory and device names
  • Also bundles a KIO plugin which shows the status of a Syncthing directory and allows to trigger Syncthing actions in Dolphin file manager
    • Rescan selected items
    • Rescan entire Syncthing directory
    • Pause/resume Syncthing directory
    • See also screenshots section
  • Also has an implementation as Plasmoid for Plasma 5 desktop
  • Allows building Syncthing as a library to run it in the same process as the tray/GUI (optional build configuration which is not enabled by default)
  • English and German localization

Does this launch or bundle Syncthing itself? What about my existing Syncthing installation?

Syncthing Tray does not launch Syncthing itself by default. There should be no interference with your existing Syncthing installation. You might consider different configurations:

  • If you're happy how Syncthing is started on your system so far just tell Syncthing Tray to connect to your currently running Syncthing instance in the settings. If you're currently starting Syncthing via systemd you might consider enabling the systemd integration in the settings (see section Configuring systemd integration).
  • If you would like Syncthing Tray to take care of starting Syncthing for you, you can use the Syncthing launcher available in the settings.
    • The Windows builds provided in the release section on GitHub come with a built-in version of Syncthing which you can consider to use. Keep in mind that automatic updates of Syncthing are not possible this way.
    • In any case you can simply point the launcher to the binary of Syncthing (which you have to download/install separately).
    • Checkout the Configuring the built-in launcher section for further details.
  • It is also possible to let Syncthing Tray connect to a Syncthing instance running on a different machine.


The screenshots are not up-to-date.

Qt Widgets based GUI under Openbox/Tint2 with dark Breeze theme

Qt Widgets based GUI under Openbox/Tint2

Under Plasma 5

Light theme

Plasmoid (light theme)

Dark theme

Plasmoid (dark theme)

Customized icons

Plasmoid (customized icons)

Settings dialog

Settings dialog

Web view

Web view Web view (dark)

Syncthing actions for Dolphin


Configuring systemd integration

The next section explains what it is good for and how to use it. If it doesn't work on your system please read the subsequent sections as well before filing an issue.

Using the systemd integration

With the system configured correctly and systemd support enabled at build-time the following features are available:

  • Starting and stopping the systemd unit of Syncthing
  • Consider the unit status when connecting to the local instance to prevent connection attempts when Syncthing isn't running anyways
  • Detect when the system has just been resumed from standby to avoid the "Disconnect" notification in that case

However, these features are optional. To use them they must be enabled in the settings dialog first.

It is recommended to enable "Consider unit status …". Note that Syncthing might still not be immediately ready to serve API requests when the systemd unit turns active. Hence it is still required to configure a re-connect interval. The re-connect interval will only be in effect while the systemd unit is active. So despite the re-connect interval there will be no connection attempts while the systemd unit is inactive. That's all the systemd integration can optimize in that regard.

Be aware that Syncthing Tray assumes by default that the systemd unit is a user unit. If you are using a regular system-wide unit (including those started with …@username) you need to enable the "System unit" checkbox in the settings. Note that starting and stopping the system-wide Syncthing unit requires authorization (systemd can ask through PolicyKit).

Required system configuration

The communication between Syncthing Tray and systemd is implemented using systemd's D-Bus service. That means systemd's D-Bus service (which is called org.freedesktop.systemd1) must be running on your D-Bus. For user units the session D-Bus is relevant and for regular units (including those started with …@username) the system D-Bus is relevant.

It seems that systemd's D-Bus service is only available when D-Bus itself is started via systemd. That is by default the case under Arch Linux and openSUSE and likely most other modern distributions where it is usually started via "socket activation" (e.g. /usr/lib/systemd/user/dbus.socket for the session D-Bus).

All of this counts for the session D-Bus and for the system D-Bus although the startup of the session D-Bus can be screwed up particularly easy. One easy way to screw it up is to start a second instance of the session D-Bus manually e.g. via dbus-run-session. When starting the session D-Bus this way the systemd integration will not work and you will likely end up with two session D-Bus processes. It is also worth noticing that you do not need to set the DBUS_SESSION_BUS_ADDRESS variable manually because the systemd file dbus.socket should take care of this.

Note that the Plasma Wayland session screwed things up in the way I've described. This has been fixed with Only spawn dbus-run-session if there isn't a session already but this change might not be available on older distributions.

Build-time configuration

The systemd integration can be explicitly enabled/disabled add compile time by adding -DSYSTEMD_SUPPORT=ON/OFF to the CMake arguments. If the systemd integration does not work be sure your version of Syncthing Tray has been compiled with systemd support.

Note for distributors: There will be no hard dependency to systemd in any case. Distributions supporting alternative init systems do not need to provide differently configured versions of Syncthing Tray. Disabling the systemd integration is mainly intended for systems which do not use systemd at all (e.g. Windows and MacOS).

Configuring the built-in launcher

The built-in launcher can be accessed and configured within the settings dialog. The GUI should be self-explaining.

It is recommended to enable "Consider process status …". Note that Syncthing might not be immediately ready to serve API requests when started. Hence it is still required to configure a re-connect interval. The re-connect interval will only be in effect while the Syncthing process is running. So despite the re-connect interval there will be no connection attempts while the Syncthing process is not running.


Use the same approach as for launching an arbitrary application via a hotkey. Make it invoke

  • syncthingtray --trigger to show the tray menu.
  • syncthingtray --webui to show the web UI.
  • syncthingctl [...] to trigger a particular action. See syncthingctl -h for details.



See the release section on GitHub.

Packages and binaries

Build instructions

The application depends on c++utilities, qtutilities and qtforkawesome and is built the same way as these libraries. For basic instructions checkout the README file of c++utilities. For building this straight, see the section below. There's also documentation about various build variables which can be passed to CMake to influence the build.

Further dependencies

The following Qt modules are required (version 5.6 or newer): core, network, dbus, gui, widgets, svg, webenginewidgets/webkitwidgets

It is recommended to use at least Qt 5.14 to avoid limitations in previous versions (see Known bugs section).

The built-in web view and therefore the modules webenginewidgets/webkitwidgets are optional (see section Select Qt module for WebView).

To build the plugin for Dolphin integration KIO is also required. Additionally, the Dolphin plugin requires Qt 5.8 or newer. To skip building the plugin, add -DNO_FILE_ITEM_ACTION_PLUGIN:BOOL=ON to the CMake arguments.

To build the Plasmoid for the Plasma 5 desktop, the Qt module QML and the KF5 module Plasma are required as well. Additionally, the Plasmoid requires Qt 5.12 or newer. To skip building the Plasmoid, add -DNO_PLASMOID:BOOL=ON to the CMake arguments.

The following Boost libraries are required: Boost.Asio, Boost.Process, Boost.Filesystem

The launcher uses these libraries by default to handle sub processes correctly (and avoid leftover processes). Add -DUSE_BOOST_PROCESS:BOOL:OFF to the CMake arguments to get rid of the dependency to Boost libraries. This disables handling sub processes and QProcess (from Qt Core) is used instead.

It is also possible to build only the CLI (syncthingctl) by adding -DNO_MODEL:BOOL=ON and -DNO_FILE_ITEM_ACTION_PLUGIN:BOOL=ON to the CMake arguments. Then only the Qt modules core, network and dbus are required.

To get rid of systemd support, add -DENABLE_SYSTEMD_SUPPORT_BY_DEFAULT to the CMake arguments. In this case the Qt module dbus is not required anymore. Note that there is no hard dependency to systemd in any case.

Building the testsuite requires CppUnit and Qt 5.8 or higher.

Building this straight

  1. Install (preferably the latest version of) the CGG toolchain or Clang, the required Qt modules and CMake.
  2. Get the sources. For the latest version from Git clone the following repositories:
    cd $SOURCES
    git clone -c core.symlinks=true c++utilities
    git clone -c core.symlinks=true
    git clone -c core.symlinks=true
    git clone -c core.symlinks=true forkawesome
    git clone -c core.symlinks=true
    git clone -c core.symlinks=true

    Note that -c core.symlinks=true is only required under Windows to handle symlinks correctly. This requires a recent Git version and a filesystem which supports symlinks (NTFS works). If you run into "not found" errors on symlink creation use git reset --hard within the repository to fix this.

  3. Configure the build
    cd $BUILD_DIR
    cmake \
     -DCMAKE_BUILD_TYPE=Release \
     -DCMAKE_INSTALL_PREFIX="/install/prefix" \
     -DFORK_AWESOME_FONT_FILE="$SOURCES/forkawesome/fonts/forkawesome-webfont.woff2" \
     -DFORK_AWESOME_ICON_DEFINITIONS="$SOURCES/forkawesome/src/icons/icons.yml" \
    • Replace /install/prefix with the directory where you want to install.
    • Checkout the Providing the font file section of qtforkawesome's README for details regarding the ForkAwesome-related parameters.
  4. Build and install everything in one step:
    cd $BUILD_DIR
    make install -j$(nproc)
    • If the install directory is not writable, do not conduct the build as root. Instead, set DESTDIR to a writable location (e.g. make DESTDIR="temporary/install/dir" install …) and move the files from there to the desired location afterwards.

Select Qt module for web view and JavaScript

  • Add -DWEBVIEW_PROVIDER:STRING=webkit/webengine/none to the CMake arguments to use either Qt WebKit (works with 'revived' version as well), Qt WebEngine or no web view at all. If no web view is used, the Syncthing web UI is opened in the default web browser. Otherwise the user can choose between the built-in web view and the web browser.
  • Add -DJS_PROVIDER:STRING=script/qml/none to the CMake arguments to use either Qt Script, Qt QML or no JavaScript engine at all. If no JavaScript engine is used, the CLI does not support scripting configuration changes.

Limitations of Qt WebEngine compared to Qt WebKit

  • When using a version of Qt older than 5.14 there is no way to allow only a particular self-signed certificate in Qt WebEngine. That means any self-signed certificate is accepted! See:
  • Qt WebEngine can not be built with GCC/mingw-w64 for Windows.
  • Security issues are not a concern because no other website than the Syncthing web UI is shown. Any external links will be opened in the regular web browser anyways.

Troubleshooting KDE integration

If the Dolphin integration or the Plasmoid don't work, check whether the files for those components have been installed in the right directories.

For instance, under Tumbleweed it looks like this for the Plasmoid:


The files for the Dolphin integration look like this under Tumbleweed:


The directory the *.so file needs to be installed to seems to differ from distribution to distribution. The right directory for your distribution can be queried from qmake using qmake-qt5 -query QT_INSTALL_PLUGINS. In doubt, just look where other Qt plugins are stored.

Actually the build system should be able to do that query automatically. It is also possible to specify the directory manually, e.g. for Tumbleweed one would add -DQT_PLUGIN_DIR=/usr/lib64/qt5/plugins to the CMake arguments.

Also be sure that the version of the plasma framework the plasmoid was built against is not newer than the version actually installed on the system. That can for instance easily happen when using tumbleweed-cli for sticking to a previous snapshot but having the latest version of the plasmoid from my home repository installed.

If the Plasmoid still won't load, checkout the log of plasmashell/plasmoidviewer/plasmawindowed. Also consider using strace to find out at which paths the shell is looking for *.desktop and *.so files.

For a development setup of the KDE integration, continue reading the subsequent section.

Contributing, developing, debugging


Currently translations for English and German are available. Qt's built-in localization/translation framework is used under the hood.

Note that syncthingctl has not been internationalized yet so it supports only English.

Add a new locale

Translations for further locales can be added quite easily:

  1. Append a new translation file for the desired locale to the TS_FILES list in connector/CMakeLists.txt, model/CMakeLists.txt, widgets/CMakeLists.txt, fileitemactionplugin/CMakeLists.txt, plasmoid/CMakeLists.txt and tray/CMakeLists.txt.
  2. Configure a new build, e.g. follow steps under Building this straight.
  3. Conduct a full build or generate only translation files via the translations target.
  4. New translation files should have been created by the build system under connector/translations, model/translations, widgets/translations, fileitemactionplugin/translations, plasmoid/translations and tray/translations and the translations folder of qtutilities.
  5. Open the files with Qt Linguist to add translations. Qt Linguist is part of the Qt Tools repository and its usage is well documented.

Extend/update existing translations

  • For English, update the corresponding string literals within the source code.
  • If necassary, sync the translation files with the source code like in step 2./3. of "Add a new locale". Check that no translations have been lost (except ones which are no longer required of course).
  • Change the strings within the translation files found within the translations directories like in step 4./5. of "Add a new locale".


  • Syncthing Tray displays also text from qtutilities. Hence it makes sense adding translations there as well (following the same procedure).
  • The CLI syncthingctl currently does not support translations.

Using backend libraries

The contained backend libraries (which provide connecting to Syncthing, data models and more) are written for internal use within the components contained by this repository.

Hence those libraries do not provide a stable ABI/API. If you like to use them to develop Syncthing integration or tooling with Qt and C++, it makes most sense to contribute it as an additional component directly to this repository. Then I will be able to take it into account when changing the API.

KDE integration

Since the Dolphin integration and the Plasmoid are plugins, testing and debugging requires a few extra steps. See Testing and debugging Dolphin/KIO plugin with Qt Creator and Testing and debugging Plasma 5 plasmoid with Qt Creator.


It is possible to turn on logging of the underlying library by setting environment variables:

  • LIB_SYNCTHING_CONNECTOR_LOG_ALL: log everything mentioned in points below
  • LIB_SYNCTHING_CONNECTOR_LOG_API_REPLIES: log replies from Syncthing's REST-API (except events)
  • LIB_SYNCTHING_CONNECTOR_LOG_EVENTS: log events emitted by Syncthing's events REST-API endpoint
  • LIB_SYNCTHING_CONNECTOR_LOG_DIRS_OR_DEVS_RESETTED: log when directories/devices are internally reset

Known bugs and workarounds

The following bugs are caused by dependencies or limitations of certain platforms. For bugs of Syncthing Tray itself, checkout the issues on GitHub.

Workaround positioning issues under Wayland

The Qt Widgets based version basically works under Wayland but there are positioning issues and the settings regarding positioning have no effect (see "List of bugs" section below). One can workaround this limitation by telling the window manager how to place the window, e.g. under Sway one could add a configuration like this:

for_window [title="^Syncthing Tray( \(.*\))?$"] floating enable, border none, resize set 450 400, move position 916 0

Workaround missing support for Windows 10 dark mode

The dark mode introduced in Windows 10 does not affect traditional desktop applications like Syncthing Tray. Unfortunately, Windows normal theming capabilities [have been removed]( removed-in-win10). So far Qt does not offer much to improve the situation (see "List of bugs" below).

However, it is possible to use Syncthing Tray's custom appearance settings to achieve a dark theming:

  • To enable dark Window borders, set the environment variable QT_QPA_PLATFORM to windows:darkmode=1.
  • To enable dark colors for Syncthing Tray's UI elements, configure a dark color palette in Syncthing Tray's settings under "Qt/Appearance". You can download and load the file as a base and tweak the colors to your liking.
  • To make the rest of the colors used by Syncthing Tray fit with the dark color palette, enable "Bright custom text colors" in Syncthing Tray's settings under "Tray/Appearance".
  • To make general icons fit with the dark color palette, configure an appropriate icon them, e.g. select "Breeze Dark" as icon theme in Syncthing Tray's settings under "Qt/Appearance".
  • To make Syncthing icons fit with the dark color palette, configure their colors in Syncthing Tray's settings under "Tray/UI icons" and "Tray/System icons". The "Use preset" button allows to select pre-defined colors suitable for a dark color palette.
  • Select the widgets style "Fusion" under "Qt/Appearance". This is required because the native styling provided by Windows for traditional desktop applications does not look very nice when using a dark color palette.

After changing these settings, restart Syncthing Tray. It is not sufficient to close the last Windows; the process needs to be restarted.

It is also possible to enable Windows' "High contrast" setting which seems to bring back the traditional theming/coloring but unfortunately doesn't look very nice overall. Check to see how Windows looks like with high contrast applied, or if you're in need for themes that look at least nicer than what's shipped with Windows.

Enable experimental support for Windows' per-monitor DPI awareness (V2)

PMv2 is not working out of the box but experimental support can be enabled in the Qt 6 build by setting the environment variable QT_QPA_PLATFORM to windows:dpiawareness=3.

List of bugs

  • Wayland limitations
    • The tray menu can not be positioned correctly under Wayland because the protocol does not allow setting window positions from the client-side (at least I don't know a way to do it). This issue can not be fixed unless Wayland provides an API to set the window position to specific coordinates or a system tray icon. See discussion on Note that the Plasmoid is not affected by this limitation.
    • While the tray menu is shown its entry is shown in the taskbar. Not sure whether there is a way to avoid this.
  • Qt bugs
  • KDE limitations
  • Systemd integration
    • This feature relies especially on the system being correctly configured. Checkout the Required system configuration section for details.

Attribution for 3rd party content

  • Some icons are taken from the Syncthing project.
  • Some icons are taken from Font Awesome (see their license).
  • Fallback icons are taken from KDE/Breeze project.